/* Base Styles & Reset */
:root {
    --primary: #2B3467;
    --primary-light: #3B4687;
    --secondary: #5D6A96;
    --accent: #0066FF;
    --text: #1E293B;
    --text-light: #64748B;
    --background: #F8FAFC;
    --surface: #FFFFFF;
    --border: #E2E8F0;
    --error: #EF4444;
    --success: #10B981;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, -apple-system, sans-serif;
    color: var(--text);
    background: var(--background);
    line-height: 1.5;
}

/* Layout & Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header & Navigation */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary);
    text-decoration: none;
}

.logo span {
    color: var(--accent);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--primary);
}

/* Breadcrumbs */
.breadcrumbs {
    padding: 1rem 0;
    margin-bottom: 2rem;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    width: 100%;
    position: relative;
}

.breadcrumbs::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100vw;
    height: 100%;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    z-index: -1;
}

.breadcrumbs-list {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.breadcrumbs-item {
    display: flex;
    align-items: center;
    color: var(--text-light);
    font-size: 0.875rem;
}

.breadcrumbs-item:not(:last-child)::after {
    content: "›";
    margin-left: 0.5rem;
    color: var(--text-light);
}

.breadcrumbs-link {
    color: var(--text-light);
    text-decoration: none;
    transition: color 0.2s;
}

.breadcrumbs-link:hover {
    color: var(--primary);
}

.breadcrumbs-current {
    color: var(--primary);
    font-weight: 500;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    text-align: center;
    background: var(--background);
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-light);
}

/* Categories Section */
.categories-section {
    margin: 4rem 0;
}

.categories-section h2 {
    font-size: 1.75rem;
    color: var(--primary);
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

.categories-section h2::after {
    content: "";
    position: absolute;
    bottom: -0.75rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.category-card {
    background: var(--surface);
    border-radius: 12px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text);
    border: 1px solid var(--border);
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.category-card:hover {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.category-icon {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.category-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.category-card p {
    color: var(--text-light);
    font-size: 0.9375rem;
    line-height: 1.5;
    flex-grow: 1;
}

.converter-count {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-top: auto;
}

/* SEO Section */
.seo-section {
    margin: 4rem 0;
    padding: 2rem;
    background: var(--surface);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.seo-section h2 {
    font-size: 1.75rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.seo-content {
    color: var(--text-light);
    line-height: 1.6;
}

.seo-content h3 {
    font-size: 1.25rem;
    color: var(--primary);
    margin: 1.5rem 0 1rem;
}

.seo-content ul {
    list-style: none;
    padding-left: 1.5rem;
}

.seo-content ul li {
    position: relative;
    margin-bottom: 0.75rem;
}

.seo-content ul li::before {
    content: "•";
    color: var(--accent);
    position: absolute;
    left: -1.5rem;
    font-weight: bold;
}

/* Popular Converters */
.popular-converters {
    margin: 4rem 0;
    background: var(--surface);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.popular-converters h2 {
    font-size: 1.75rem;
    color: var(--primary);
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

.popular-converters h2::after {
    content: "";
    position: absolute;
    bottom: -0.75rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
}

.converters-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.converter-item {
    background: var(--background);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    text-decoration: none;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
}

.converter-item:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.converter-item .converter-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
    background: none;
    text-align: left;
}

.converter-title {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text);
    flex: 1;
}

.converter-arrow {
    color: var(--accent);
    font-size: 1.25rem;
    padding: 0 0.5rem;
}

.common-values-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.common-value {
    background: var(--surface);
    padding: 0.25rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
    color: var(--text);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.converter-item:hover .common-value {
    border-color: var(--primary);
}

/* Converter Page Styles */
.converter-header {
    background: linear-gradient(to bottom, var(--surface), var(--background));
    padding: 3rem 0;
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

.converter-header::before {
    display: none !important;
}
#swapButton {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--accent);
}

.converter-header h1 {
    font-size: 2rem;
    color: var(--primary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.3;
}

/* Calculator Card */
.calculator-card {
    background: var(--surface);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    padding: 2rem;
    margin: 2rem 0;
}

.calculator-inputs {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1.5rem;
    align-items: center;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-light);
}

.calculator-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 1rem;
    transition: all 0.2s;
}

.calculator-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.conversion-arrow {
    font-size: 1.5rem;
    color: var(--secondary);
}

/* Common Values */
.common-values {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
}

.common-values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 0.75rem;
    margin-top: 0.75rem;
}

.common-value-link {
    display: block;
    padding: 0.5rem;
    text-align: center;
    background: var(--background);
    border-radius: 6px;
    color: var(--text);
    text-decoration: none;
    transition: all 0.2s;
}

.common-value-link:hover {
    background: var(--primary);
    color: var(--surface);
}

/* Footer */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 4rem 0;
    margin-top: 4rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section a {
    color: var(--text-light);
    text-decoration: none;
    display: block;
    padding: 0.5rem 0;
    transition: color 0.2s;
}

.footer-section a:hover {
    color: var(--primary);
}

.footer-bottom {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--primary);
}

/* Formula and Examples Sections */
.formula-section,
.examples-section {
    margin-top: 3rem;
    padding: 2rem;
    background: var(--surface);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.formula-section h2,
.examples-section h2 {
    font-size: 1.5rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.formula-content,
.examples-content {
    color: var(--text);
    line-height: 1.6;
}

.formula-content p,
.examples-content p {
    margin-bottom: 1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .converter-header {
        padding: 2rem 0;
    }

    .converter-header h1 {
        font-size: 1.5rem;
        padding: 0 1rem;
    }

    .calculator-inputs {
        grid-template-columns: 1fr;
    }

    .formula-section,
    .examples-section {
        padding: 1.5rem;
        margin-top: 2rem;
    }
    
    .conversion-arrow {
        transform: rotate(90deg);
        margin: 1rem 0;
    }
    
    .nav-links {
        display: none;
    }
    
    .hero h1 {
        font-size: 2rem;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
    }
}

/* Category Page Styles */
.category-header {
    background: linear-gradient(to bottom, var(--surface), var(--background));
    padding: 4rem 0;
    text-align: center;
    margin-bottom: 2rem;
    position: relative;
}

.category-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100vw;
    height: 100%;
    background: linear-gradient(to bottom, var(--surface), var(--background));
    z-index: -1;
}

.category-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 1rem;
}

.category-description {
    font-size: 1.2rem;
    color: var(--text-light);
    max-width: 800px;
    margin: 0 auto;
}

.converters-section {
    margin: 3rem 0;
}

.converters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.converter-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text);
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
}

.converter-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.converter-main {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.from-unit, .to-unit {
    flex: 1;
}

.unit-name {
    font-weight: 500;
    display: block;
    color: var(--text);
}

.unit-symbol {
    color: var(--text-light);
    font-size: 0.9rem;
}

.converter-arrow {
    color: var(--accent);
    font-size: 1.25rem;
    padding: 0 1rem;
}

/* Category SEO Section */
.category-seo-section {
    margin: 4rem 0;
    padding: 2rem;
    background: var(--surface);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.category-seo-section h2 {
    font-size: 1.75rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.converter-list {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin: 1.5rem 0;
}

.converter-list li a {
    color: var(--text);
    text-decoration: none;
    padding: 0.75rem;
    border-radius: 6px;
    display: block;
    transition: all 0.2s;
    background: var(--background);
}

.converter-list li a:hover {
    background: var(--primary);
    color: var(--surface);
}

.category-info {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    color: var(--text-light);
    line-height: 1.6;
}

/* Responsive Design */
@media (max-width: 768px) {
    .category-header {
        padding: 2rem 0;
    }
    .category-header h1 {
        font-size: 2rem;
    }
    .category-description {
        font-size: 1rem;
        padding: 0 1rem;
    }
    .converters-grid {
        grid-template-columns: 1fr;
    }
    .converter-list {
        grid-template-columns: 1fr;
    }
    .breadcrumbs {
        padding: 0.75rem 0;
        margin-bottom: 1.5rem;
    }
    .breadcrumbs-list {
        gap: 0.25rem;
    }
    .breadcrumbs-item {
        font-size: 0.8125rem;
    }
    .popular-converters {
        margin: 2rem 0;
        padding: 1.5rem;
    }
    .converters-list {
        grid-template-columns: 1fr;
    }
    .converter-item .converter-header {
        flex-direction: row;
        text-align: left;
    }
}
.popular-converters .converter-header,
.popular-converters .converter-item .converter-header {
    background: var(--surface) !important;
}